In recent years, performances of western religious music in China have echoed across a fragile political landscape. During the cultural revolution, which ended 30 years ago, all western music was vilified and those who practiced it were silenced. Christians, meanwhile, became victims of the assault on "feudal superstition" and western influence.

In the decades that followed, and as dogma gave way to pragmatism and economic links with the rest of the world, western music was welcomed. Grand concert halls were built, a new generation of classical musicians like pianist Lang Lang burst onto the international stage, the Three Tenors were invited to perform in China.

The Communist party watched the spread of Christianity with a far more apprehensive gaze because it presented people with an alternative authority (God) and an alternative set of rules. State-run Chinese websites still cite instances of foreign missionaries using religion "to serve in the interests of colonialism and imperialism" stretching back to the 19th century as if it had all happened just yesterday.

Now, quietly and without publicity, the Chinese authorities have let it be known that western religious music should no longer be performed in concert halls. It's an unexpected decision, and one for which there is no obvious explanation or trigger.

As someone who's taken part in performances of the Messiah as part of an international choir in Beijing's 1,600-seat Forbidden City concert hall, I know that our collective purpose was to share music that we loved. We knew that many people coming to the concerts would never have heard this music before. Like any gathering of western musicians, there were atheists and agnostics in our ranks as well as people of various faiths. It was not an exercise in evangelism.

Of course, the music may speak for itself, and perhaps even party officials have been moved in ways that have alarmed them. In general, however, audiences for performances of western religious music seem to be there primarily for the musical experience.

In any case, the spread of Christianity in China has not originated in the concert halls of the cities. Churches in the cities are full – both state-sponsored and unofficial – but so are churches in many areas of the countryside, where no one may ever have heard a note of Handel or Bach. It's almost impossible to estimate how many Christians there are in China, largely because many of them worship in secret. But there are said to be up to 70 million, which is roughly the same as the number of Communist party members. There is also believed to be a substantial overlap in membership of the two groups.

Although the leadership sees Christianity as a western imposition, most of the spread seems to be home grown. Indeed, rural house church Christianity is far tougher than many in the west would recognise, with worship sometimes conducted at five in the morning to escape the eyes of the authorities.

The ban eliminates large swathes of western classical music from the programmes of musicians both Chinese and western, at a time when Beijing has invested millions in an architecturally stunning concert hall. But it seems to me that it is a symptom of a larger political malaise. It has been an intensely challenging year for Chinese leaders – they have had to manage natural disasters, international condemnation of food safety cover-ups, and a massive logistical challenge in the Olympics. Communist party leaders have struck out at the west over perceived support for Tibetan separatists. At times when the Communist party feels insecure, it often turns against the west and western influence. It seems to me that this is what has happened here. Unfortunately, paranoia often bodes ill for reform in China.